Voltage regulator



Sept. 20, 1949. R. G. L TURNEAU VOLTAGE REGULATOR Filed Feb. 11, 1947V w\ N\DN QNNN w,

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Patented Sept. '20, 1949 VOLTAGE REGULATOR Robert G. Le Tourneau, Longview, Tex., assignor to R. G..-Le Tourneau, Inc., Stockton, Calif., a.

corporation of California l Aiiiieetonrebruery 11, 1947, serial 5111.727305 The present'finvention relates to, Vand'it is anu objecty to'provide, va vnov-fel4r voltage regulator for A. C.' alternators or' generators; the invention contemplating an electricalsystem whereby excitation of the A. C. generator is positively and automatically 'effected indirect proportin to the load. f

Y Another object of the invention is to provide a voltage (exciter currentlf-regulating system for A. C.r generators,` lwhich* comprises a current transformer having n'its' primary vinterposed in series in the load`4` circuit between the A. C. generator and the load j thepotential of `such transformer as induced-5in pr'OpQrtiOnjto the loadin the secondary *of the transformerbeing 4carried through anA.. C.-D. Cf yrectifier and'then fed as a D.`C.` exciter currentl tothe field ofthe A. C'. generator.'

Thus, the `rexciter. current* delivered te the A. C.' generator is'constantly maintained 'in correct and necessary proportion 'to' the load `cur-v rent; increase or" decrease in' the-load causing automatic and correspondingvariation in such excitation current. -In-*otherworda the system automatically compensates for alternator regulation.

It is also an object of the invention to provide a voltage regulatingsystemwhich prevents overloading of the A. C. generator. 11"

A further object of the invention is to provide a voltage regulating system, for the purpose described, which is especially useful ron tractor propelledimplements whereina tractor enginel driven A.. C.- generatori's. employed as l-thef'current source for an electric `actuating motor of the implement. In such an installation, wherein the A. C. generator is not only subject to widely varying load, but also to speed changes occasioned by the tractor engine accelerating and decelerating, the described regulating system is of great advantage.

A further object of the invention is to provide a practical voltage regulator, and one which will be practical for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

The gure of the drawing is a diagrammatic view of one form of circuit which the system may employ.

Referring now more particularly to the characters of reference on the drawings, the circuit which is here shown to illustrate the system in- 4 claims. (c1. S22-27') cludes an A. C.*a1t'ernator or generator, indicated at Ik, which generatorincludes an alternator field 2. f l

The load' circuit*isfnthreeiphase and is numbered s; such load circuit leading to connection with a source of-"AfCuload, indicated diagrammatically at 4. a,

When the describedl'voltage' regulating system is employed vnFa?tracto'r"'propelled implement, the A. C.' generator 'I is mounted on the tractor and driver'rfhyl tlfie tractor engine, thus being subject to'ac'celeration and deceleration with the-flatter( `jIn-'suchflanginstallation the A. C. load 4 Weuldfbe,"'for exam'plaan electric motor on the implementarranged inactuating relation to 'a movable partof'the latter.

' The load circuitl 3 has 'thecorresponding primary coils 5,"ofa currentAY transformer S, interposed'in series therein if The secondary coils of such current transformer 6 are indicated at 1.

The` output leads i8 `rff-thesecondary coils I extend to and connect Witha rectier, preferably of vdry plateftypefonejside of the rectier being grounded, asf' at` I0. @The other side of the,

rectifierV 9 connectsgbya-lad iI 'I, to 'one terminal of the alternator eld '2"of the A.k C. generator I ;v the opposite--terininalpffsaid*field 2r being grounded', a'satIZ, bya lead I3.` U

Initial exciter current forthe field 2 of the generator I isfed t o the lead v I'Ilfrun a battery circuit I4, including abattery 'I5orr a generator circuit I6 includinga; DQjQCLfgenerator I'I and a D. C. voltage regulator I8; L Irina tractor Dropelled implementgtliewbattery `circuit and the generator circuitfcouldtbe the conventional ones included in the tractor.

Thus, under no load conditions the open circuit voltage of the A. C. generator is controlled by eld excitation supplied by any one of the usual means, such as the described battery circuit I4 or generator circuit I6.

Upon a load being imposed on the circuit 3, the load current passing through the seriesconnected primary coils 5 of the current transformer 5 induces a potential in the secondary coils 1 in direct proportion to the A. C. load 4.

This potential as induced in such secondary coils 1 is fed directly through the rectifier 9, and from said rectier delivers to the lead I I and thence to the field 2. While the battery circuit I4 or the generator circuit I6 furnishes initial eX- citation current, once the circuit is in operation the excitation is eiected from the rectifier 9 in direct and correct proportional amount to the lad.

A blocking rectifier I9 is interposed in the lead II between the rectifier and the junction of the battery circuit III and generator circuit I6; this blocking rectifier preventing back feeding from the main rectifier 9 into said battery circuit; or generator circuit, which would be undesirable.

It will be seen that with the described voltage regulating system, the exciter current delivered to the eld 2 is automatically and positively main.- tained, regardless of variation in the A. C. load 4, or speed fluctuation of the A. C. generator I; this being accomplished in short by excitaticn ci the field 2 by a rectified current induced from the load circuit of the A. C. glllfllr, and Ain prg)T portion to the load imposed thereon.

From the foregoing description it will be seen that there has been produced such a Voltage reguE lating system as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the voltf age regulating system, still in practice such devia.- tions from such detail may be resorted tc as do not form a departure from the spirit of the invention, as described in the appended claims.

Having thus described the invention, the following is claimed as new and useful and upon which Letters Patent are desired:

l. A voltage regulating system for an A. C. gen-I erator having a field, the output o f the A. C. gen.- erator being coupled to a lead circuit; said system comprising means to induce an A. C. poten.- tial from the load circuit in direct proportion te the load, means to rectify said A. C. potential to a D. C. exciter current, and circuit means to feed such exciter current directly to the eld oi the A, C. generator; there being an independent source of initial D. C. exciter current, separate from said load circuit, connected to said circuit means, and a blocking rectifier between said independent source of initial exciter current and said circuit means.

2, A voltage regulating s ystem for an A. C. generator, having a eld, the output of the A. C. generator being coupled to a load circuit, .said system comprising an A. C..D. C. rectifier, a cur.- rent transformer having its primary in series with the load circuit and its secondary connected to the A. C. input Side of the rectier, and `circuit means connecting the D. C. output side of the rectifier directly to the field of the A. C. generator whereby to deliver D. C. exciter current to said eld in direct proportion to the load in the load circuit; there being an independent source of initial D. C. exciter current, separate from said lill load circuit, connected to said circuit means, and a blocking rectier interposed between said circuit means and independent source of initial D. C. exciter current.

3. A voltage regulating system for an A. C. generator, having a field, the output of the A. C. generator being coupled to a load circuit, said system comprising an A. Q.D. C. rectier, a current transformer having its primary in series with the load circuit and its secondary connected to the A. C. input side of the rectifier, and circuit means connecting the D. C. output side of the rectifier directly to the field of the A. C. generator whereby tc deliver D. C, exciter current to said eld in direct proportion to the load in the load circuit; there being two independent sources of initial De C. exciter current; said sources being separate from the load circuit, one source being a battery including a battery circuit, and the other source a D. C. generator including a generator circuit, the battery circuit andthe generator circuit being in parallel and connected to Said Circuit means, and a blocking rectier interposed between said circuit means and the parallel battery and generator circuits to prevent the rectifier output from feeding back through said last named circuits.

4. A voltage regulating system for an A. C. generator. having .a eld, the `Output of the A. C. generator being coupled te a load circuit, said system comprising an A. C..D. C. rectifier, a current transformer having its primary in series with the load Circuit and its secondary connected, to the A, C, input side of the rectifier, and circuit means @Qnnecting the D. C. output side of the rectiiier directly to the eld of the A. C. generator whereby to deliver D. C. exciter Current to Said field in direct proportion to the ,load in the load Circuit; there beingr an independent source of initial D. C. exciter current, separate from said load circuit, connected to said circuit means, and current blocking means interposed between said circuit means and independent source or initial D. C. exciter current operative to prevent current feed back to said separate source from said circuit f means.

ROBERT G. LE TOURNEAU.

REFERENCES CITED The following references are of record in the le of this patent:

STATES PATENTS Number Name nate 737.027 Dobrowolsky Apr. 11, 1905 2,066,919 West Jan. 5, 1937 

